1. Field of the Invention
The present invention relates to a crucible furnace with a furnace body, a fireproof floor and a changeable crucible.
2. Description of the Prior Art
The crucibles of crucible ovens are composed of a fireproof material such as quartzite or magnezite. They are preferably produced by pulverization. These crucibles get worn out in use. Therefore, they must be replaced regularly at intervals of about 3 to 6 weeks. In addition to this, the crucibles are customarily broken up with a pneumatic hammer in the furnace and the broken pieces are cleaned out. This work is attended by a considerable amount of troublesome noise and dust and is very time consuming.
The avoidance of a long interruption of furnace usage is known from the DE-AS No. 10 50 025, which discloses an induction crucible furnace in which the crucible, induction coil and magnet yoke are combined into an independent replaceable unit with corresponding rigidity. During repair on one of the combination parts, the replacement part is lifted out of the furnace body with a crane so that the repairs can take place in a more appropriate place. In the meantime, furnace use can continue with a replacement part.
From the DEOS No. 24 00 519 a procedure is known for the removal of a crucible from a crucible furnace, as well as a crucible furnace for the execution of the procedure. This known crucible furnace possesses a removeable fireproof floor. For the removal of the crucible the furnace is laid on the side and the floor is dismantled. Finally, the furnace part which contains the crucible is again placed upright and the crucible is pushed out downardly. Moreover, a pour spout which is formed on the crucible must be specially removed. To simplify the pushing out of the crucible, it has been proposed that the crucible and the oven frame be formed slightly conical.
Such removable floors are, however, heavy and cumbersome. Besides that, the construction for the fastening of the floor on the furnace is relatively complicated as is shown in the DEAS No. 20 58 093 in which a converter with a removeable base is described.